Multipurpose Photodetector Amplifier for Dynamic Image Capture
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Solution Overview
Problem
Image capture devices are optimized for specific modes of operation (low ambient light, bright ambient light, or high amplification) due to competing requirements, limiting their utility in varying conditions and necessitating separate designs for each mode.
Innovation Solution
A system and method that utilize a unit cell with a Capacitor Transimpedance Amplifier (CTIA), Source Follower per Detector (SFD), and Direct Injection (DI) subcircuits, controlled by a column amplifier, allowing the same components to perform different modes of operation based on a control signal, enabling a single image sensor to adapt to various applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the image sensor is optimized for low ambient light scenes with low noise and low capacitance components, then sensitivity is improved, but the device cannot handle bright ambient light scenes requiring higher capacitance
Solution Approach 1:
The patent implements dynamic switching between three operational modes (CTIA, SFD, DI) based on scene conditions. The system automatically selects the appropriate mode depending on whether the scene is low light, bright light, or requires high amplification, allowing the same hardware to adapt its characteristics in real-time rather than being fixed for one condition
Solution Approach 2:
The patent creates a universal image sensor that can perform all three capture modes (CTIA for low light, SFD for bright light, DI for high amplification) using the same physical components. This multi-functionality eliminates the need for separate optimized sensors for different scene types, allowing one device to replace multiple specialized devices
2Quantity of substance
If the image sensor is optimized for bright ambient light scenes with higher capacitance, then charge storage capability is improved, but sensitivity for low ambient light scenes deteriorates
Solution Approach 1:
The system dynamically adjusts its operational characteristics by switching between modes. When in SFD mode for bright light scenes, higher capacitance components are engaged for charge storage. When switching to CTIA mode for low light scenes, the system engages low capacitance components to maintain sensitivity, thus adapting charge storage capability to scene requirements
Solution Approach 2:
Different components with different capacitance values are used for different operational modes. The system selects appropriate components locally for each mode: low capacitance components for CTIA mode (low light) and high capacitance components for SFD mode (bright light), optimizing performance for each specific condition
3Power
If the image sensor is optimized for high amplification, then signal amplification capability is improved, but adaptability to other modes deteriorates
Solution Approach 1:
The patent designs a universal sensor that incorporates all three capture modes (CTIA, SFD, DI) within the same device, allowing it to provide high amplification when needed (DI mode) while also being capable of low light capture (CTIA mode) and bright light capture (SFD mode), thus maintaining versatility while providing specialized high amplification capability
4Measurement precision
If separate image sensors are designed for each mode of operation, then performance for that specific mode is improved, but device complexity and number of components increases
Solution Approach 1:
The patent merges three separate capture mode functionalities (CTIA, SFD, DI) into a single image sensor device. By combining these modes in one unified hardware platform with shared components, the system achieves mode-specific performance for each condition while reducing the total number of devices from three separate sensors to one multi-functional sensor
Solution Approach 2:
The invention creates a universal image sensor that performs all three capture modes using the same physical components and circuitry. This multi-functionality allows one device to replace multiple specialized devices, reducing system complexity while maintaining optimized performance for each operational mode through software-controlled mode switching
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables a single image sensor to operate across a wide dynamic range (>110dB) and change modes without affecting accumulated charge, preserving light intensity data, thus enhancing versatility and performance in different scene conditions.
Implementation Method 1
Image sensors used in image capture devices generally generate charge in proportion to light intensity received at that location
Data Source
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AI summary
In certain embodiments, a system is provided for image capture that includes a unit cell that includes a Capacitor Translmpedance Amplifier (CTIA) subcircuit, a Source Follower per Detector (SFD) subcircuit, and a Direct Injection (DI) subcircuit. The unit cell may operate using one of the subcircuits selected in response to a control signal. A column amplifier may be coupled to the unit cell. The column amplifier may be operable to receive an intermediate signal from the unit cell and couple components of the column amplifier corresponding to the selected subcircuit in response to the control signal. The column amplifier may generate an output signal from the intermediate signal using the coupled components of the column amplifier.